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Date: Thu, 10 Mar 2016 08:10:03 -0800
Message-ID: <CABPqkBT0u0_YGDe2yHLrx6utj0rBiJOrstAhOLsjptAK-rU-oA@mail.gmail.com>
Subject: Re: [PATCH 2/3] perf/x86/pebs: add workaround for broken OVFL status
 on HSW
From: Stephane Eranian <eranian@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>, LKML <linux-kernel@vger.kernel.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        "mingo@elte.hu" <mingo@elte.hu>, "Liang, Kan" <kan.liang@intel.com>,
        Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>
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On Thu, Mar 10, 2016 at 5:53 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Mon, Mar 07, 2016 at 01:18:40PM +0100, Peter Zijlstra wrote:
>> On Mon, Mar 07, 2016 at 11:24:13AM +0100, Peter Zijlstra wrote:
>>
>> > I suspect Andi is having something along:
>> >
>> >  lkml.kernel.org/r/1445458568-16956-1-git-send-email-andi@firstfloor.org
>> >
>> > applied to his tree.
>>
>> OK, I munged a bunch of patches together, please have a hard look at the
>> end result found in:
>>
>>   git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git perf/core
>
> So while running tip/master I just triggered the "irq loop stuck" warn
> on my IVB, with status==1, and PMC0 didn't look weird at all.
>
> I've not seen that for a fair while. But it does show it still happens
> on not quite antique hardware.

Yes, as I said, tip.git is missing something, with Andi's missing 3
patches I do not get
that. But with them, I was getting the problem I described earlier, so
I just posted a
patch to handle that particular case where bit 62 is not set, yet PEBS
counters show
overflow. Test it.

Thanks.